1. Field of Use
The present invention relates to bus systems and, more particularly, to bus priority networks.
2. Prior Art
Prior systems provided a distributed priority network for resolving bus access among different requestors on a priority basis. An example of such a system is found in the patent application of George J Barlow, et al entitled, "Flexible Distributed Bus Priority Network, Ser. No. 07/593,436, filed on Oct. 5, 1990 which is now a U.S. Pat. No. 5,150,466.
Where an interface was shared between two types of requestors, the timing was adjusted to the rate of the slowest requestor. More specifically, the delays were set to different amounts depending upon whether the requestor was a central processing unit (CPU) or a memory unit to ensure proper priority resolution. An example of such a system is disclosed in U.S. Pat. No. 4,901,226.
When the number of different requestors which can share a common bus interface is increased, it becomes difficult to establish delays without a substantial increase in complexity. Moreover, the timing adjustment to the slowest requestor reduces overall system performance. Also, the prior approach is not readily adaptable to change in the number and type of requestors sharing a common interface.
Accordingly, it is a primary object of the present invention to provide a high performance priority network interface.